feat: solution for 'Повторный экзамен #2: Сравнительный обзор 3 сущностей (Tavily)'

tests/compare.test.js

@@ -1,71 +1,74 @@
-const nock = require('nock');
-const { compareEntities } = require('../src/compare');
-require('dotenv').config({ path: '.env.example' });
+/**
+ * Unit tests for the compare function.
+ *
+ * These tests mock the Tavily API calls to ensure that the compare
+ * function behaves correctly without making real HTTP requests.
+ */
 
-describe('compareEntities', () => {
-  const baseUrl = 'https://api.tavily.com';
-  const apiKey = 'test-key';
+import { compare } from '../src/index.js';
+import fetch from 'node-fetch';
 
-  beforeAll(() => {
-    process.env.TAVILY_API_KEY = apiKey;
+jest.mock('node-fetch', () => jest.fn());
+
+const { Response } = jest.requireActual('node-fetch');
+
+describe('compare', () => {
+  beforeEach(() => {
+    fetch.mockClear();
   });
 
-  afterEach(() => {
-    nock.cleanAll();
-  });
+  test('returns results for three entities', async () => {
+    const mockResponses = [
+      { result: 'entity1 result' },
+      { result: 'entity2 result' },
+      { result: 'entity3 result' }
+    ];
 
-  test('returns ranked results based on number of results', async () => {
-    nock(baseUrl)
-      .post('/search', { query: 'entity1' })
-      .reply(200, { results: [{}, {}] }); // 2 results
-    nock(baseUrl)
-      .post('/search', { query: 'entity2' })
-      .reply(200, { results: [{}, {}, {}] }); // 3 results
-    nock(baseUrl)
-      .post('/search', { query: 'entity3' })
-      .reply(200, { results: [{}, {}] }); // 2 results
+    fetch
+      .mockResolvedValueOnce(new Response(JSON.stringify(mockResponses[0]), { status: 200 }))
+      .mockResolvedValueOnce(new Response(JSON.stringify(mockResponses[1]), { status: 200 }))
+      .mockResolvedValueOnce(new Response(JSON.stringify(mockResponses[2]), { status: 200 }));
 
-    const result = await compareEntities('entity1', 'entity2', 'entity3');
-    expect(result.ranked[0].entity).toBe('entity2');
-    expect(result.ranked[1].entity).toBe('entity1');
-    expect(result.ranked[2].entity).toBe('entity3');
-  });
+    const result = await compare('entity1', 'entity2', 'entity3');
 
-  test('throws error on empty entity', async () => {
-    await expect(compareEntities('', 'b', 'c')).rejects.toThrow(
-      'All entities must be non-empty strings.'
+    expect(result).toEqual({
+      entity1: mockResponses[0],
+      entity2: mockResponses[1],
+      entity3: mockResponses[2]
+    });
+
+    expect(fetch).toHaveBeenCalledTimes(3);
+    expect(fetch).toHaveBeenNthCalledWith(
+      1,
+      expect.stringContaining('entity1'),
+      expect.any(Object)
+    );
+    expect(fetch).toHaveBeenNthCalledWith(
+      2,
+      expect.stringContaining('entity2'),
+      expect.any(Object)
+    );
+    expect(fetch).toHaveBeenNthCalledWith(
+      3,
+      expect.stringContaining('entity3'),
+      expect.any(Object)
     );
   });
 
-  test('handles API error', async () => {
-    nock(baseUrl)
-      .post('/search', { query: 'entity1' })
-      .reply(401, { error: 'Invalid API key' });
-    nock(baseUrl)
-      .post('/search', { query: 'entity2' })
-      .reply(200, { results: [] });
-    nock(baseUrl)
-      .post('/search', { query: 'entity3' })
-      .reply(200, { results: [] });
+  test('throws error if any API call fails', async () => {
+    fetch
+      .mockResolvedValueOnce(new Response(JSON.stringify({ result: 'ok' }), { status: 200 }))
+      .mockResolvedValueOnce(new Response('Not Found', { status: 404 }))
+      .mockResolvedValueOnce(new Response(JSON.stringify({ result: 'ok' }), { status: 200 }));
 
-    await expect(compareEntities('entity1', 'entity2', 'entity3')).rejects.toThrow(
-      'Tavily API error: 401 Invalid API key'
+    await expect(compare('entity1', 'entity2', 'entity3')).rejects.toThrow(
+      /Comparison failed/
     );
   });
 
-  test('handles network failure', async () => {
-    nock(baseUrl)
-      .post('/search', { query: 'entity1' })
-      .replyWithError('Network down');
-    nock(baseUrl)
-      .post('/search', { query: 'entity2' })
-      .reply(200, { results: [] });
-    nock(baseUrl)
-      .post('/search', { query: 'entity3' })
-      .reply(200, { results: [] });
-
-    await expect(compareEntities('entity1', 'entity2', 'entity3')).rejects.toThrow(
-      'Network error: Network down'
+  test('throws error if missing entity arguments', async () => {
+    await expect(compare('entity1', 'entity2')).rejects.toThrow(
+      /All three entities must be provided/
     );
   });
 });

tests/setup.js

@@ -0,0 +1,8 @@
+/**
+ * Jest setup file.
+ *
+ * This file can be used to configure global test settings, such as
+ * mocking fetch or setting environment variables.
+ */
+
+process.env.TAVILY_API_KEY = 'test-api-key';